1. Field of the Invention
This invention relates to broadcast communication systems and, more particularly, to broadcast data propagated in a digital television system.
2. Description of the Background Art
In a conventional Digital Television (DTV) system, video data, audio data, and broadcast data are multiplexed into one program transport stream by a transmitter for downstream processing by at least one receiver. The transmitter, besides being composed of video and audio generators, includes a broadcast data generator for providing supplementary services to the broadcast community; broadcast data does not conform to any standards or format. Examples of broadcast data include: (1) Web home pages; (2) Uniform Resource Locator (URL) of a Web site; and (3) computer programs executable upon a personal computer.
In the receiver, a user of the receiver can select from a set of DTV channels using a tuner to detect an individual modulated DTV channel signal propagated at a given carrier frequency. A demodulator detects the incoming transport stream for the given channel, and the demodulated stream is split into video data, audio data, and broadcast data by a demultiplexer. A video circuit then reconstructs the video from the video data for display on a display device; similarly audio is reconstructed from the audio data.
The broadcast data is processed by a central processing unit. In particular, if the incoming broadcast data is representative of a home page on the Web, or a URL, this data is stored on a disk. If the incoming broadcast data is a program, the program may be executed by the CPU or stored for later execution. In this case, the result of executing the program, if a display is required, will be generated by the CPU and be delivered to the video circuit for processing and display on the display device. Whether or not the data is to be stored, and when a program is to execute, is under control of the user.
Broadcast data oftentimes is transitory, so a user who does not store the broadcast data in the receiver when it is propagated will not have another opportunity to receive the data. Thus, if a user's receiver is turned-off, inadvertently or intentionally, when data of possible interest is broadcast, the data will be missed by the user. Typically, the receiver is turned-off intentionally while the user, for example, is away from home or has retired for the night, so the user may reduce electricity costs.
Also, it may be possible that a user not having an interest in broadcast data at one time may, at a later time, have renewed interest in the data. Therefore, there are situations in which the user desires to "browse" and find interesting data later from a stored body of data. Representative of techniques for storing broadcast data for later recall is the subject matter disclosed in U.S. Pat. No. 5,617,565 issued to Augenbraun et al, entitled "Broadcast Interactive Multimedia System" (BIM System), and assigned to the assignee of this patent application. In this reference, broadcast data in the form of data elements is captured based upon a user profile established initially by the user, and which profile is dynamically altered as the user selects incoming data elements. The BIM System teaches and suggests that all components of the receiver must be energized at all times in order to capture the data and process the data, including the step of dynamic modification of the user profile. Moreover, the BIM System teaches and suggests that all data elements inherently include the data itself, for example, a newspaper article, a technical paper, stock market data, or a magazine article. There is no teaching or suggestion that a data element may be, in essence, a pointer which points to the actual data itself, such as a URL address which points to a Web page. Nor is there any teaching or suggestion that the data may be an executable program which may be invoked at the discretion of the user.
As discerned from the foregoing discussion, the art is devoid of teachings and suggestions related to systems which provide the combined, desirable properties of: low power consumption; capture of broadcast data of interest to the user in the low power consumption mode; the ability to browse for interesting broadcast data at a time following the actual broadcast of the data when the entire receiver is in the full-ON or high power consumption mode; using a pointer to provide the location of data which can be obtained once the receiver is full-ON to thereby mitigate storage requirements in the low power consumption mode; invoking executable code as conveyed by the broadcast data at the discretion of the user; and transfer of the stored data from a first memory operational in the lower power consumption mode to a second memory operational only during the full-ON mode for manipulation by the user.
It should be emphasized, by way of distinguishing the BIM System from the method and concomitant circuitry in accordance with the present invention, that the principles of the BIM system can be incorporated into the operation of the method and circuitry of the present invention so as to more closely match the user's interest at any given moment, but the BIM System does not include the aforementioned properties which are strictly the domain of the present invention.